Story on police deaths not supported by statistics

June 12, 2007|ELLEN MAHER

A Tribune article (April 29) purported to show that police in South Bend have a higher death rate than those in other similarly-sized Midwestern cities. The article employed some data analysis worthy of a place in Darrell Huff's classic "How to Lie with Statistics." Maybe The Tribune editors were dozing that day; I hope they weren't simply blinded by the opportunity for one more sensational headline in the week following the tragic shooting at the Wooden Indian Motel. The writer used data from the Officer Down Memorial Page Inc., a Web page claiming to list every police officer death while on duty in the United States since 1791. I have no particular quarrel with that site, although its fairly broad criteria for inclusion can be misleading. As the article notes, it includes officers who died fighting crime as well as those who died of accidental or natural causes while on duty. For the sake of argument, however, I'll accept the ODMP data. The Tribune writer claims to have compared the ODMP death numbers for "41 comparably-sized cities in the Midwest." Whether these are really comparable is debatable. The populations of the 10 cities he found to have the highest police death rates range from just over 79,000 to more than 144,000. (It is impossible to determine the population range for all 41, since the article lacks selection information or a complete list of the cities included.) A further difficulty: Some of the cities in question are fairly compact and self-contained, while others (including South Bend) are metropolitan areas which function as socioeconomic wholes. The ODMP data honor the city limits, but police death risks do not. My main problem with the article, however, is the inclusion of police deaths from 1791. The Tribune headline asks "Do police here face higher risks?" Readers are presumably interested in the present tense, and the population data are current (2005). Why, then, include every ODMP-listed death from more than 200 years of record-keeping? Were all of those 41 cities even in existence during that whole period? As an exercise, I went back and recalculated the death rates for the 10 cities listed in The Tribune graphic accompanying the article, but using a comparable starting point, 1945 (an arbitrary date, but at least one well-honored in sociological analysis). For the sake of comparison and simplicity, I accepted the nonsense of calculating a "death rate" by dividing a historically-derived number of deaths by a single-point population number. Some battles are simply not worth the effort. Based on just that changed starting date, the picture changes dramatically. South Bend drops from second to sixth in the list, while Gary jumps from fourth to first and Hammond moves up from seventh to second. It turns out that 10 of the 15 deaths recorded for South Bend occurred prior to 1945. The city of South Bend has experienced two police deaths in just about a year. Those deaths are tragic, but they cannot be fairly judged to constitute a trend, much less a statistically-meaningful assessment of our officers' death risk. As a community, we need to look at the risk factors which exist now -- easy access to handguns comes to mind -- and address those risk factors. We can't do much about the risks that were around in 1840. Ellen Maher is a retired sociologist and librarian and a resident of South Bend.